<div class="row form-group">
  <div class="col-sm-6">
    <label class="col-sm-3 control-label">Razón Social</label>
    <div class="col-sm-6">
      <input type='text' class='form-control' name='f_txt_razon_social' placeholder='Razón social'>
    </div>    
  </div>

  <div class="col-sm-6">
    <label class="col-sm-3 control-label">Responsable</label>
    <div class="col-sm-6">
      <?php
      $opcionesResponsable = array('');
      $defaultSelection = 0;
      if(isset($listado_responsables)){ 
        foreach ($listado_responsables as $resp) { 
          $opcionesResponsable[$resp->id] = $resp->descripcion;
        }   
      }
      echo form_dropdown('f_sel_responsable', $opcionesResponsable, $defaultSelection, "id = 'f_sel_responsable' class = 'form-control'");
       ?>
    </div>
  </div>
</div>

<div class="row form-group">
  <div class="col-sm-6">
    <label class="col-sm-3 control-label">Tipo Documento</label>
    <div class="col-sm-6">
      <?php
      $opcionesTipo = array('');
      $defaultSelection = 0;
      if(isset($listado_documentos)){ 
        foreach ($listado_documentos as $tipo) { 
          $opcionesTipo[$tipo->id] = $tipo->descripcion;
        }   
      }
      echo form_dropdown('f_sel_documento', $opcionesTipo, $defaultSelection, "id = 'f_sel_documento' class = 'form-control'");
       ?>
    </div>    
  </div>

  <div class="col-sm-6">
    <label class="col-sm-3 control-label">N° Documento</label>
    <div class="col-sm-6">
      <input type='text' class='form-control' name='f_txt_numero_doc' placeholder='Número de documento'>
    </div>
  </div>
</div>